Method of forming a closed corner in a hollow rectilinear metal workpiece



July 16, 1963 F. LE TARTE 3,097,684 7 METHOD OF FORMING A CLOSED CORNER IN A HOLLOW RECTILINEAR METAL WORKPIECE Fil'ed Jan. 14, 1960 s Sheets-Sheet 1 l I I. I [I I I I II [I I I I II II II II I I I I I I I I I I I I I I I I I I I I I Fi I 71 Y rI A4 I L 2%? E 5 INVENTOR. ran/ Le Tu-te QMIWW ATTORNEYS July 16, 1963 Filed Jan. 14, 1960 F. LE TARTE METHOD OF FORMING A CLOSED CORNER IN A HOLLOW RECTILINEAR METAL WORKPIECE 3 Sheets-Sheet 2 INVENTOR. Hank Le Erie ATTORNEYS July 16, 1963 Filed Jan. 14, 1960 5 Sheets-Sheet 3 INVENTOR. Frank Le 7511? AT TOR NEYS United States Patent METHOD OF FORMIN G 1i CLOSED CORNER IN A HOLLOW RECTILINEAR METAL WORKPIECE Frank Le Tarte, Wales Township, St. Clair County, Mich.,

assignor to The Le Tarte Company, Inc., a corporation of Michigan Filed Jan. 14, 1960, Ser. No. 6,336 Claims. (Cl. 153-2) My invention relates to a new and useful improvement in a frame construction and relates particularly to the method of forming the same and the mechanics for carrying out the method. In forming metal frames for such articles as doors, windows, window screens, storm windows and etc., it is customary to use extruded and formed metal strips. A die is formed for notching the strip at proper locations so that the strip may be bent at the notched portion into the desired shape. This involves the expense of making a die for each different shape, and in the use of the die, the operation is a slow process. It also is impossible to use this method if the metal strip happens to be a tube as in FIG. 1 of such a length as to prohibit the use of 'a mandrel die.

In the present invention, I use a pair of saws for notching. This eliminates the necessity of forming a die for each job and provides a means for quickly and inexpensively notching the strips of metal at any desired point, whether the strips are long and tubular in design or not. I It is an object of the present invention to provide a universal mechanism and a method whereby this notch ing may be done inexpensively and rapidly, on all shapes of extruded or formed metal strips, tubes or solids.

Another object of the invention is the provision of a method which will be highly efiicient in use.

Other objects will appear hereinafter.

It is recognized that various modifications and changes may be made without departing from the invention, and

it is intended that the present disclosure shall be con sidered to be but the preferred embodiment.

Forming a part of this application are drawings in which,

FIG. 1 is a strip of metal showing the notching operation, this drawing does not show a true picture of the operation because only twonotches are shown, whereas four are needed to form the frame,

FIG. 2 is a partially completed frame folded,

FIG. 3 is the completed frame folded,

FIG. 4 is a bottom plan view of FIG. 3,

FIG. 5 is a sectional view taken on line 55 of FIG. 2,

FIG. 6 is a sectional view taken on line 66 of FIG. 2,

FIG. 7 is a fragmentary plan View of the mechanism used in carrying out the process,

FIG. 8 is a sectionalview taken on line 88 of FIG. 7,

FIG. 9 is a perspective view of the mechanism used in the invention.

In carrying out the operation, I use a mechanism quite similar to that shown in United States Letters Patent No. 2,722,731 issued to George M. Le Tarte, on November 8, 1955. In this mechanism, I use a supporting bed 9, supported by suitable standards 10. Mounted on this bed are saw fences including blocks 11 and 12. Mounted on the block 12 forming part of one fence is an angle iron 13, having the upwardly projecting flange 14. Mounted on the block 11 and forming part of the other fence is the angle iron 15 having the upwardly projecting flange 16. Each of these angle irons is mounted on its respective block in the same manner, so that a description of one will sufiice for both. Formed in the block 11 or 12 is a groove 20, communicating with a slot 17 formed therethrough. Projected through this slot and through the angle iron is a bolt 18, having a head 19 "ice which is adapted to slide in the groove 20. It will be noted from FIG. 7 that these grooves are extended diagonally of the length of the angle iron and of the block. When the nut on the bolt 18 is loosened it is believed obvious that the angle iron may be moved angularly of the block, and when moved to the proper position a tightening of the nut on the bolt 18 will fix the angle irons in relation to the bed 9.

Mounted on the bed 9, as shown in FIG. 8, is a block 21 which, as shown in FIG. 7, is provided with a pair of slots 22 in which engage the ribs 23 extending outwardly from the vertically extending support 24. Formed in this block 21 is an opening 25 registering with the opening 26 formed in the bed 9. Slidable on. the support 24 is a head 27, which engages in the guide grooves 28 formed in the support 24, so that the head may move upwardly and downwardly on the support 24. Extending outwardly from the head 24 is a supporting rib 29, projecting from opposite sides of which is an arm 30 to provide a T-shaped construction. The ends of these arms 30 are angularly turned to provide the supporting portion 31, which serves to support a bushing 32. The construction at each of the portions 31 is the same, so that a description of one will suffice for both. Journalled in the bushing 32 is a stub shaft 33, the opposite end 34 of which is journalled in a bushing 35 mounted in the head 27. Mounted on each of the stub shafts 33 is a guard. Mounted on one of the stub shafts 33, at one side of this guard wall 37, is a rotary saw 39 and a rotary saw 40 is mounted on the other stub shaft 33 within the guard housing. It will be noted that the axes of these rotary saws extend angularly to each other. It will be noted that saw 39 is of slightly larger diameter than the saw 40, and that these saws over-lap. The periphery of the saw 39 is flush with the outer face of the saw 40' and there is very little space between the saws at the overlapping portion. This is a departure from the disclosure of the patent referred to above, and this is necessary so that in the operation, there will be no head or rib formed where the notch is cut into the material.

An electric motor 41 is used to drive through the belts 42 and 43 the pulleys 44 and 45 mounted on the stub shaft which rotates the saw 39. An electric motor 46 serves to drive through the belts 47 and 48 the pulleys 49 and 50 which are mounted on the shaft carrying the rotary saw 40. Each of these motors is similarly mounted and, as shown in FIG. 8, the motor is provided with a bed 53. Projecting downwardly from the bed 53 is a pair of spaced lugs 54, which are pivotally connected to the lug 55 projecting upwardly from the bed 9 so as to swingably mount the motor in position. The unpivoted end of the motor 46 is supported by a spring 56, which embraces a stud 57 which is connected to and projects upwardly from the bed 9. This construction is desirable in order to permit the raising and lowering of the saw supporting structure without disturbing or impairing the connections between the saw carrying shafts and the driving motors.

Secured to and projecting outwardly from the head 27 is a bracket 58 divided into a pair of lugs 59, which are pivotally connected to one end of the actuating bar 60. The lower end of this bar 60 is pivotally connected to a rod 61 which connects to a lever or pedal 62 pivotally mounted on a crossbar 63 of the supporting table. A spring 64 is connected to the bed 9 and to the point of pivot of the arm 61, and the bar 60, in order to retain the structure normally in an elevated position. The bed 9 has slots formed therein to accommodate the saws 39 and 40 and in the position shown in FIG. 8, the saw is in the elevated position. In order to move the saw downwardly into operative position, the operator would 3 press downwardly on the free end of the pedal or lever 62. This downward movement would, of course, be against the tension of the spring 64 thus permitting the operator to move the saw downwardly at a slow rate of movement. This is quite necessary where the saws are being used for metal sawing.

In use the strip 71 to be sawed is placed upon the block 12 and brought into engagement with the upwardly extending flanges 14 and -16 of the angle irons, so that the strip to be cut spans the distance between the adjacent ends of these angle irons. It will be noted from FIG. 7 that the adjacent ends are cut on the bevels which correspond to the angularly positioning of the saws 39 and 40. When the material is in proper position, the operator, through stepping on the pedal 62, would bning the saws downwardly into engagement with the strip to be cut.

The frame is formed from a strip of extruded or formed material which has at least two sides extended angularly to each other, and one side 72 of the strip 71 may be termed the back-side. As the saws are brought down on the strip 71, the portion of the strip 71 will be sawed excepting the back-side and consequently, there will be removed from the strip 71 a triangular piece of metal which appears obvious from an examination of FIG. 1. By having the saws located in the manner indicated, the triangular piece of metal is cut free without leaving any bead or rib on the inner face of the backside 72. When the cut has been made, the strip 71 may be folded at the notched portion to provide the frame shown in FIG. 2 and FIG. 3. Inserted in the meeting ends 83 and 84 of the frame is a block 85 of material such as wood, steel, aluminum or the like, which is held in position by suitable screws 86.

The process, therefore, consists of bringing a pair of saws extending angularly relatively to each other into engagement with the piece to be notched, but bringing these saws into engagement in such a manner that a clean cut will be provided without deforming or collapsing the cross section of the work piece and that no rib or projection will be left on the inner face of the back-side 72. The planes of the saw cuts meet at a common desired folding point at the adjacent face of the back side 72 as shown in FIG. 1.

By adjusting the location of the blocks 11 and 12 on the bed 9 the structure may be adjusted for accommodating workpieces of diiferent thickness of back sides 72 while at the same time retaining the same angle of cut with both of the saws.

As shown in FIG. 9, a standard 70 projects upwardly from the bed 9 and serves as a support for the outlet box 66 to which lead the feed wires 67. The support 70 would also support the switch box 69 from which would proceed the wires 67 for operating the motors.

In the disclosure I have illustrated one of the saws being of larger diameter than the other. This, however, would not be necessary as the saws might be of the same diameter and the mounting of the saws adjusted so that the over-lapping referred to will be present.

What I claim is:

1. The method of forming a closed corner from a hollow rectilinear metal workpiece including the steps of selecting an elongated workpiece having a closed shaped hollow cross section structure which has at least two sides extending angularly to each other, supporting the workpiece on a bed, relatively positioning the workpiece and a pair of angularly disposed circular saws for cutting engagement by both saws of all but one of said sides without deforming the cross section of the workpiece and so that the apex of the resulting notch is in a position to permit the workpiece to bend about said one side to form a closed corner, rotating said saws, simultaneously moving the saws through relatively angularly disposed planes of rotation of the respective saws, wherein the path of one of the saws overlaps that of the other saw and the periphery of the overlapping saw is tangent to the plane of the outer surface of said overlapped saw when said saws pass through said workpiece, wherein the kerf of the resulting cut of the overlapping saw lies in the plane of the outside edge of the resulting cut of the overlapped saw, said paths being in such close proximity that the path of the periphery of the overlapped saw is juxtaposed the plane of the inside face of the overlapping saw so that substantially all material will be removed from the workpiece at the apex of the resulting notch and bending said one side at said apex wherein said side defines the periphery of said corner and continuing said bending until the opposing edges of the workpiece cut by said saws join each other to define a closed corner.

2. The method according to claim 1, wherein the step of relatively positioning a pair of angularly disposed circular saws includes the step of mounting said saws in a fixed relationship to each other, wherein the step of simultaneously moving the saws is accomplished by simultaneously moving the saws throughout the cutting step.

3. The method according to claim ;1, wherein the step of simultaneously moving said saws includes the step of simultaneously cutting said workpiece with both of said saws.

4. The method according to claim 1, wherein the step of simultaneously moving said saws includes the step of maintaining the axes of the saws in the same horizontal plane.

5. The method according to claim 1, wherein the step of simultaneously moving said saws includes the step of maintaining the overlapping relationship of said saws.

References Cited in the file of this patent UNITED STATES PATENTS 861,735 Klein July 30, 1907 1,439,801 Davis Dec. 26, 1922 1,967,262 Robinson et al. 'July 24, 1934 2,094,991 Lang Oct. 5, 1937 2,609,848 Schneider Sept. 9, 1952 2,722,731 Le Tarte Nov. 8, 1955 2,800,932 Scott July 30, 1957 2,803,869 Brauchler Aug. 27, 1957 2,837,160 Vera et al. June 3, 1958 

1. THE METHOD OF FORMING A CLOSED CORNER FROM A HOLLOW RECTILINEAR METAL WORKPIECE INCLUDING THE STEPS OF SELECTING AN ELONGATED WORKPIECE HAVING A CLOSED SHAPED HOLLOW CROSS SECTION STRUCTURE WHICH HAS AT LEAST TWO SIDES EXTENDING ANGULARLY TO EACH OTER, SUPPORTING THE WORKPIECE ON A BED, RELATIVELY POSITIONING THE WORKPIECE AND A PAIR OF ANGULARLY DISPOSED CIRCULAR SAWS FOR CUTTING ENGAGEMENT BY BOTH SAWS ALL BUT ONE OF SAID SIDES WITHOUT DEFORMING THE CROSS SECTION OF THE WORKPIECE AND SO THAT THE APEX OF THE RESULTING NOTCH IS IN A POSITION TO PERMIT THE WORKPIECE TO BEND ABOUT SAID ONE SIDE TO FORM A CLOSED CORNER, ROTATING SAID SAWS, SIMULTANEOUSLY MOVING THE SAWS THROUGH RELATIVELY ANGULARLY DISPOSED PLANES OF ROTATION OF THE RESPCTIVE SAWS, WHEREIN THE PATHE OF ONE OF THE SAWS OVERLAPS THAT OF THE OTHER SAW AND THE PERIPHERY OF THE OVERLAPPING SAW IS TANGENT TO THE PLANE OF THE OUTER SURFACE OF SAID OVERLAPPED SAW WHEN SAID SAWS PASS THROUGH SAID WORKPIECE, WHEREIN THE KERF OF THE RESULTING CUT OF THE OVERLAPPING SAW LIES IN 